Description
- Abstract:
- Ecosystem structure is a fundamental property of terrestrial ecosystems. Understanding the variability in ecosystem structure is crucial for projecting the response of terrestrial ecosystems to changing climate and intensified human activities. However, it is unclear what explains the variation in ecosystem structure across the world’s biomes due to the lack of ecosystem structure measurements at appropriate spatial scales and regions. First, measurement characteristics or algorithms used to quantify ecosystem structure could influence our conclusions. Second, given the widespread human modification over the land surface and their influence on terrestrial ecosystems, if the variation in ecosystem structure is still primarily predicted by the physical environment remains unclear. My dissertation addressed these questions using data from airborne and spaceborne lidar sensors. In chapter 1, I found that the decoupled impact of measurement characteristics can be different from visual interpretation and that sampling completeness of drone lidar depends on pulse density, scan-angle range and height above ground. In chapter 2, I found that while human impacts account for some variation in ecosystem structure, the variability is still primarily predicted by the physical environment. In chapter 3, I found that there is variation in the relationship between ecosystem structure and aboveground biomass density that was not accounted for by the current aboveground biomass density data product from GEDI lidar. This demonstrates the possibility of reconsidering current ways of stratifying the aboveground biomass density models and informs where to prioritize training data collection. Together, my dissertation enhances our understanding of terrestrial ecosystems by demonstrating the necessity of testing certain assumptions when using remotely sensed data to investigate ecosystem structure and revealed the complexity of using lidar to understand the variation in terrestrial ecosystems.
- Notes:
- Thesis (Ph. D.)--Brown University, 2024
Citation
Zhang, Dafeng,
"Using Lidar to Enhance Understanding of Terrestrial Ecosystem Structure"
(2024).
Ecological and Evolutionary Biology Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:4a2954je/
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Ecological and Evolutionary Biology Theses and Dissertations
Theses and Dissertations for the Ecological and Evolutionary Biology department....